Gasification and reduction behavior of iron ore-carbon composite under high pressure

Iron oxide-carbon composites have a potential to play a significant role in mitigating CO ₂ emission from the ironmaking process. However, efficiency of gasification and reduction of iron ore-carbon composite seem to be limited under the condition of blast furnace. In this study, effect of pressure on the gasification and reduction of the composite was evaluated. Hematite reagent and ore powders were mixed with graphite powder to make composite samples. They were heated up to different target temperatures at a heating rate of 0.167°C/s under different pressures. Weight loss fraction was obtained by the difference between sample masses before and after reduction. Gasification temperature decreased and weight loss fraction at the target temperature increased with an increase in pressure. Further, molar ratio of CO to (CO+CO ₂) in the outlet gas decreased with increasing pressure, after it reached the coexisting condition of wustite and metallic iron phases. These results show that an increase in pressure leads to increase in the reaction rate of indirect reduction. Further, this can be attributed to an increase in the partial pressure of CO gas and the prevention of gasification reaction.